Port is a sweet, fortified dessert wine originally from Portugal. The basic types of port are vintage and non-vintage. Because of its high sugar content, port does not deteriorate as quickly as wine after opening, but does have an optimal temperature for serving.
Vintage ports are only made in specific years based on the quality of the grape crop in that year. Once purchased, port should be stored lying down in a cool, dark, dry place at a temperature of approximately 55 degrees, similar to wine. The optimal serving temperature for vintage port is 66 degrees F.
Ruby port is bottle-aged and is the cheapest and most extensively produced type of port. After fermentation, it is stored in tanks made of concrete or stainless steel to prevent oxidation and preserve its rich ruby color. Ruby port does not generally improve with age and should be drunk upon release at 57 degrees F.
Tawny ports are barrel-aged wines made from red grapes that are aged in wooden casks. As a result, they gradually take on a tawny or golden-brown color. They should be stored lying down at 55 degrees F. Tawny ports can be drunk upon release and should be served at 57 degrees F.
References and ResourcesGoodCooking.com: Port
Wine Intro: Wine Serving Temperature Guidelines
WineDefinitions.com: Recommended Serving Temperature By Wine Type